Immunologic characterization and ultrastructural correlations for 125 cases of B- and T-cell leukemias: studies of chronic and acute lymphocytic, prolymphocytic, lymphosarcoma cell and hairy cell leukemia, Sézary's syndrome, and other lymphoid leukemias.

Peripheral blood from 125 patients (160 specimens) with various types of lymphoid leukemias was evaluated for B- and T-cell markers (E rosettes, C3 and Fc receptors, and surface immunoglobulin). B-cell leukemias (comprised 82% of the series and included chronic lymphocytic leukemia (69/71 cases), acute lymphocytic leukemia (1/18 cases), lymphosarcoma cell leukemia (15/18 cases), prolymphocytic leukemia (one case), plasma cell leukemia (one case), hairy cell leukemia (12/12 cases), and leukemic phase of "histiocytic" lymphoma and Waldenström's macroglobulinemia (one case each). Within the B-cell group, certain leukemias exhibited distinct patterns of lymphocyte surface markers. Three cases of lymphosarcoma cell leukemia revealed both T and B cell markers (E-rosette formation and monoclonal SIg). T-cell leukemias comprised 12% of the series and included chronic lymphocytic leukemia (2/71 cases), acute lymphocytic leukemia (11/18 cases), and Sézary's syndrome (2/2 cases). In eight cases of acute lymphocytic leukemia, the majority of the cells demonstrated no definable markers (non-B, non-T cell type). Ultrastructural studies, performed in selected cases, were correlated with immunologic findings. Distinctive morphologic features were observed for different variants of B- and T-cell leukemias. Neoplastic cells of T-cell leukemias revealed a greater nuclear irregularity than B-cell proliferations, as assessed by the nuclear contour index (ratio of circumference to the square root of the nuclear area). The cytoplasmic feature most predictive of immunologic cell type was abundant rough endoplasmic reticulum, suggesting plasmacytoid differentiation, observed in some B-cell proliferations.